The realities, do's and dont's of boosting a 1985 928 5SPD
04-09-2017, 07:47 PM
#61
Race Car
What's the buy in for this option these days?
And mightn't one end up at the same cross-roads? I guess that would just be for bored (fine, sleeved) & stroked.
That VEMS webpage is interesting, wish more Porsche/928 info were available for those of us in need of some tutelage.
And mightn't one end up at the same cross-roads? I guess that would just be for bored (fine, sleeved) & stroked.
That VEMS webpage is interesting, wish more Porsche/928 info were available for those of us in need of some tutelage.
04-09-2017, 08:48 PM
#62
Burning Brakes
Thread Starter
Given I'm a noob to turbo and boost, I may need to stick with the stock system and get a shark tuner. Once I'm over the learning curve for turbo and ignition systems, I may decide to upgrade.
I think we should keep the conversation going about the different systems in use and the experiences. (New Thread) I'm okay continuing the discussion here too.
I think we should keep the conversation going about the different systems in use and the experiences. (New Thread) I'm okay continuing the discussion here too.
Last edited by cpayne; 04-10-2017 at 08:39 PM.
04-09-2017, 08:57 PM
#63
Burning Brakes
Thread Starter
Lets talk about inter coolers.
I will need one soon. Moving the MAF and hope to set the CO and idle. Installing the air temp sensor John recommended in an earlier post. Roger sent me one " Bosch 0280 130 085"
I will need one soon. Moving the MAF and hope to set the CO and idle. Installing the air temp sensor John recommended in an earlier post. Roger sent me one " Bosch 0280 130 085"
Last edited by cpayne; 04-10-2017 at 08:40 PM.
04-10-2017, 03:32 PM
#64
Administrator - "Tyson"
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04-13-2017, 03:10 PM
#65
Inventor
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The S2/S3 EZ-F board has a problem with cold soldering of the EPROM holder. Once you disturb the chip, it may stutter or cut out once in a while, or stop running entirely. It is easily repaired by reflowing the solder. (The LH doesn't have this problem.)
I have a stack of EZ-Fs which need fixing. When I was making my S3 chips I had two with the same problem which nearly drove me crazy trying to find what I thought was a bug in my new code.
Ha! The factory programming was made with a git'r'dun attitude. The factory S2-GTS digital maps are fixed and there is no compensation for wear, weather, or other factors besides O2 feedback. WOT is set for cold weather at sea-level on the Autobahn (which ends up being very rich everywhere else). If you do tune it yourself, unfortunately almost all of the nut and bolts that are available are not exposed by the SharkTuner software.
Newer, aftermarket ECUs have tons more processing power and much improved software to create maps simply (even automatically). They can be set to use a wideband O2 (or two) to hit different AFRs at particular loads and rpm. Individual cylinder (self-)tuning by AFR and knock feedback, boost control, traction control... plus, they have tons of inputs and outputs...oh my!
That said, the inherent restrictions of the S3/S4- intake (exhaust, ignition system, etc.) will still limit stock power output to ~300 rwhp so it is difficult to make a total mess of tuning them yourself. The higher the power output over stock, the better the case for going with an aftermarket ECU.
I have a stack of EZ-Fs which need fixing. When I was making my S3 chips I had two with the same problem which nearly drove me crazy trying to find what I thought was a bug in my new code.
The piece of the puzzle left out of using a 3rd party is you are now tuning 100% of the map from scratch instead of just the boosted areas, and yes this can be a big deal. I see people all over car forums downplaying this but they simply do not appreciate the work involved with tuning a car from scratch. Making sure the maps are fully tuned for every possible scenario from ice cold mornings to death valley heat at all engine temperature ranges. Most cars I come across with 3rd party ECU's are tuned with the "good enough" attitude and they keep a laptop handy just in case. That doesn't' cut it for me and the reason why I went with the twin dizzy arrangement for my 81. I wanted to start with the base maps.
Todd has spent hundreds of hours tuning his turbo 928 and he's been doing this for the better part of three decades.
Todd has spent hundreds of hours tuning his turbo 928 and he's been doing this for the better part of three decades.
Newer, aftermarket ECUs have tons more processing power and much improved software to create maps simply (even automatically). They can be set to use a wideband O2 (or two) to hit different AFRs at particular loads and rpm. Individual cylinder (self-)tuning by AFR and knock feedback, boost control, traction control... plus, they have tons of inputs and outputs...oh my!
That said, the inherent restrictions of the S3/S4- intake (exhaust, ignition system, etc.) will still limit stock power output to ~300 rwhp so it is difficult to make a total mess of tuning them yourself. The higher the power output over stock, the better the case for going with an aftermarket ECU.
Originally Posted by Niels Bohr
An expert is a person who has made all the mistakes that can be made in a very narrow field.
04-13-2017, 04:02 PM
#66
Rainman
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PorKen...
Would you be willing to provide general tuning "consulting" for boosted S3 operators not using your chips or even a standard DME?
Just curious about the particulars of the open-chamber S3 head knock sensitivity and timing requirements vs say more known quantities like the S4 head.
Would you be willing to provide general tuning "consulting" for boosted S3 operators not using your chips or even a standard DME?
Just curious about the particulars of the open-chamber S3 head knock sensitivity and timing requirements vs say more known quantities like the S4 head.
04-13-2017, 07:49 PM
#67
Inventor
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I haven't run any boost so I'm not much help there, but N/A, the S3 is quite forgiving in regards to knock in my experience. (AFAIK, high static compression is offset by the blow-down of the long duration cams.)
With the stock S3 EZ-F, it is difficult to keep the power output consistent (on the dyno) unless you are really careful about intake air temperatures. I think a S3 engine with dual knock sensors, a S4- hall sensor, and an aftermarket ECU would be sweet. (A second knock sensor could be fitted with a custom or modified MAF/TB housing.)
What I've always wanted to test is the effect of cam timing under boost. N/A, you can get a bit more torque by advancing, but most any retard just loses power everywhere. I think this might be a different story with boost.
With the stock S3 EZ-F, it is difficult to keep the power output consistent (on the dyno) unless you are really careful about intake air temperatures. I think a S3 engine with dual knock sensors, a S4- hall sensor, and an aftermarket ECU would be sweet. (A second knock sensor could be fitted with a custom or modified MAF/TB housing.)
What I've always wanted to test is the effect of cam timing under boost. N/A, you can get a bit more torque by advancing, but most any retard just loses power everywhere. I think this might be a different story with boost.
03-19-2020, 01:43 PM
#68
I just updated the Vampire unit, adding a rev limiter.
For coil on plug systems, a knock-finder display is available, showing which cylinders (coils) are being retarded. The display is not very useful for waste spark or distributor ignition, as it only shows which coils are being retarded.
For coil on plug systems, a knock-finder display is available, showing which cylinders (coils) are being retarded. The display is not very useful for waste spark or distributor ignition, as it only shows which coils are being retarded.